Microsoft Technology Licensing, LLC

Paul R Swan

David Matthew Kruse

Mathew George

Roopesh C Battepati

James T Pinkerton

Daniel Edward Lovinger

Mingdong Shang

Tom Jolly

Michael C Johnson

Described are embodiments directed at persistent handles that are used to retain state across network failures and server failovers. Persistent handles are requested by a client after a session has been established with a file server. The request for the persistent handle includes a handle identifier generated by the client. The server uses the handle identifier to associate with state information. When there is a network failure or a server failover, and a reconnection to the client, the handle identifier is used to identify replayed requests that if replayed would create an inconsistent state on the server. The replayed requests are then appropriately handled.

Transparent failover

A connection state system is described herein that allows a client to resume a connection with a server or a different replacement server by remotely storing client state information in association with a resume key. The system provides a resume key filter operating at the server that facilitates the storing of volatile server state information. The state information can include information such as oplocks, leases granted to a client, and in-flight operations on a file handle. The resume key filter driver sits above the file system, which allows multiple file access protocols to use the filter. Upon a failover event, such as a server going down or losing connectivity to a client, the system can bring up another server or the same server and reestablish state for file handles held by various clients using the resume key filter.

Providing transparent failover in a file system

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Sammamish, WA, United States of America

Paul R Swan